The present invention relates to a light guiding apparatus suitable for use in an indicator or the like for indicating the state of control and setting in, for example, electronic appliances.
In an indicator of, for example, an electronic appliance, a light ray supplied from a light emitting means such as a light emitting diode (LED) and so on is emitted from an outer casing of the device to the outside to indicate the state of control or setting in, for example, the electronic appliance for the outside. In that case, a light guiding device 40 as shown in, for example, FIGS. 1A and 1B is used in conventional devices.
In the examples shown in FIGS. 1A and 1B, the light guiding device 40 is formed by molding transparent, or milky white colored, light transmitting resin in a pillar form. One end of the light guiding device 40 faces the outside from an aperture 42 formed through an outer casing 41 of the device. In front of the other end of the light guiding device 40, a light emitting means 43 is disposed and controlled according to the state of control or setting in, for example, the electronic appliance.
When the light emitting means 43 is lighted in this device by a control signal supplied from the circuit board 44, its light ray is incident on the other end of the light guiding device 40, propagated through the inside of the light guiding device 40, and emitted from the one end of the light guiding device 40. In other words, when the light emitting means 43 is lighted, the one end of the light guiding device 40 inserted in the aperture 42 of the outer casing 41 of the device is lighted. Thereby, the state of the control or setting in, for example, the electronic appliance is indicated to the outside.
In this light guiding device, the circuit board 44 is typically disposed horizontally within the outer casing 41 of the appliance, and the aperture 42 is formed in the front face of the outer casing 41. In order to provide the light emitting means 43 in front of the other end of the above described light guiding device 40, therefore, a LED forming the light emitting means 43 is raised from the circuit board 44 by using a holder 45, for example, and disposed at a desired position as shown in FIG. 1A.
In this method, however, an extra part such as the holder 45 or the like is needed. Due to the increased numbers of parts and increased assembly workings, a problem of an increase in cost is posed. Alternatively, vertical disposition of the circuit board 44 as shown in FIG. 1B is also conducted. However, a space for disposing the circuit board 44 vertically is needed. For an appliance desired to be especially thin, the vertical disposition of the circuit board 44 cannot be adopted.
The above described indicator is sometimes required to effect indication on both the front face and the top face of the appliance. For example, a control panel 50 incorporating therein a control means for manually controlling the power on/off, channel up/down, and tone volume increase/decrease, an indicator for indicating their control and setting states as one body or the like is disposed on a so-called bezel portion or the like of an outer frame of a display face of a television set as shown in FIG. 2.
As shown in FIG. 3, the control panel 50 includes, for example, a group of switches such as a power on/off switch 52, a channel up/down switch 53, a tone volume increase/decrease switch 54, an input selection switch 55 and an input setting switch 56 or the like, and a group of indicators such as a power on indicator 57 and an indicator 58 indicating input setting or the like. In addition, statements 59 indicating contents of such control/setting switches and so on are also described thereon.
And in the control panel 50, indications of the indicators 57 and 58 are conducted on two faces, i.e., the front face and the top face of the control panel 50. In the case where such indicators 57 and 58 conducting the indication on the two faces are to be formed, various light guiding devices 70 as shown in FIGS. 4A to 4D, for example, have been used in the conventional appliance.
The light guiding device 70 shown in FIG. 4A is formed so as to have a nearly pentagonal cross-section. By making a light ray from a light emitting means 71 incident to a bottom face a of the light guiding device 70 toward a vertex b, two faces c and d having the vertex b sandwiched therebetween become luminous. In this configuration, however, a holder 72 for disposing the light emitting means 71 toward the vertex b or the like is needed. Due to an increase in the number of parts and so on, a problem of an increase in cost is posed.
The light guiding device 70 shown in FIG. 4B is formed so as to have a rectangular cross-section. By making light rays from light emitting means 71e and 71f incident respectively to two inner faces e and f of the light guiding device 70, two outer faces g and h thereof become luminous. In this configuration, however, two light emitting means 71e and 71f, the holder 72 and the like are needed. In this case as well, a problem of an increase in cost caused by an increase in the number of parts is posed.
In FIG. 4C, a notch h having a triangular cross-section is formed on a top face g side of the light guiding device 70 formed so as to have a rectangular cross-section. By making a light ray from the light emitting means 71 incident to a bottom face i of the light guiding device 70, the incident light ray is reflected by a face j of the notch and therefore a front face k becomes luminous. In addition, the light ray is transmitted through the face j and a top face g also becomes luminous. Thus, the two outer faces g and k each become luminous.
In this structure, however, forming the notch h on the top face g of the light guiding device 70 causes a change in design on the outer side of the device. In other words, the notch h on the top face g of the light guiding device 70 is formed on the outside of the device. Therefore, it is necessary to alter the outer design of the device so as to take this notch h into consideration.
In FIG. 4D, curved faces m and n are formed on the light guiding device 70. A light ray from the light emitting means 71 is made incident to the light guiding device 70 from its bottom face p, reflected by these curved faces m and n, and thereby guided to a front face q and a top face r of the light guiding device 70. The faces q and r thus become luminous. However, this structure has a problem that, in particular, the light emission on the top face r is not favorable. This structure has also a problem that the volume of the light guiding device 70 itself becomes large and installation thereof is not easy.